Electrochromic devices use electrochromic materials of which the optical absorption properties (such as absorption wavelength and absorbance) are changed through an electrochemical redox reaction and are applied to, for example, display apparatuses, variable-reflectance mirrors, and variable transmission windows.
Such electrochromic devices include organic electrochromic devices, and PTL 1 discloses an organic electrochromic device having an organic electrochromic layer that is a layer of a solution in which organic low-molecular-weight electrochromic materials having different absorption wavelengths have been dissolved in a solvent. The organic electrochromic device disclosed in PTL 1, however, has some regions in which a color balance changes in a color-display mode because the molecules of the electrochromic materials in the organic electrochromic layer have different diffusion coefficients.
Such a change in a color balance is inadequate when the organic electrochromic device is used as, for example, a unit for adjusting the amount of light in an imaging apparatus [e.g., neutral density (ND) filter] or as a color filter in a display apparatus and therefore needs to be reduced.